1. Field of the Invention
The present invention relates to a signal processing apparatus, a signal processing method, a recording medium and a program, and more particularly, to a signal processing apparatus, a signal processing method, a recording medium and a program, which are useful for fingerprint collation.
2. Description of the Related Art
Nowadays there is technology for fingerprint collation by reading a user's fingerprint in order to carry out authentication for identification purposes.
Conditions for reading a fingerprint vary from user to user as well as with differences in environment. Users which are subject to fingerprint reading may include people that sweat easily, or conversely, those who hardly sweat. Further, reading the fingerprint of a user with cream or the like applied to one's hand sometimes causes a mark of fingerprint-shaped greasy stains to be left on the surface of the sensor.
In the conventional art, amplitude of an output signal from a sensor has been used to determine whether a finger is in contact with the sensor or not.
For instance, a conventional fingerprint collation apparatus starts fetching in a fingerprint image, after positioning of a finger is detected through a capacitance between a pair of electrodes mounted at a finger rest position (See, for instance, Japanese Patent Laid-open No. 11-197135).